In the pneumatic grippers of the type mentioned above, the body and jaws are usually made of steel and have a rather complicated and difficult design which is created by means of machining. These grippers are inverted to create in the body a chamber for each control piston and for the guides for the jaws, and to provide complementary guide jaws for joining and sliding in the body. In addition, the mutual guide means between the body and jaws thus obtained are not always reliable and precise as desired.